David Gill's increasingly fragile relationship with Manchester United's supporters has led to concerns within Old Trafford that the bad feeling could have a negative impact on his son's breakthrough into the first-team squad.

Oliver Gill, a 19-year-old centre-half, was on the bench when United returned to the top of the Premier League with a 3-0 defeat of Fulham on Sunday but his name was booed when it was read out before kick-off.

The teenager has also been verbally abused during some of United's reserve matches and conducted one post-match interview on the in-house TV station while supporters in the background responded by singing a song to denigrate Malcolm Glazer's ownership of the club.

United are hoping the crowd's reaction last Sunday was a one-off during a highly sensitive timeat Old Trafford with Gill, the club's £1.8m-a-year chief executive, facing heavy criticism for aligning himself with the Glazers having previously sided with the protesters when he tried to talk down the takeover in 2005. Several banners have appeared at matches, one accusing him of "protecting his salary not the club". Security has subsequently been tightened, with the club employing bouncer-style minders in and around the directors' area .

The targeting of Gill's son, albeit by a minority, is the first time that an element have gone against Sir Alex Ferguson's request to ensure that the protests do not affect the team. On the fans' websites many have objected to one of the club's up-and-coming players being made a scapegoat. Equally, others have talked openly about targeting the player as a way of getting at his father.

Gill signed his first professional contract last July and the Surrey-born defender has impressed Ferguson with his performances for the reserve team. The manager and the rest of the coaching staff are aware of the booing and Ferguson is understood to be disappointed. Other officials have insisted it is not a serious cause for concern but acknowledged that it goes against the manager's request for everyone to get behind the team.

United's supporters usually pride themselves on not turning against their own players but this has not always been the case, as Darren Fletcher and Kieran Richardson could testify – or, indeed, Rio Ferdinand after he was photographed dining with Chelsea's then chief executive Peter Kenyon when he was in dispute about the terms of a proposed new contract.

Even Ryan Giggs has been targeted, with ironic cheers when he was substituted during one poor patch, but this is the first time a player has been targeted because of his surname.

Gill was promoted to the squad on Sunday because of injuries to Wes Brown, Rafael da Silva, Jonny Evans and John O'Shea. He is now expected to return to the reserves, with Evans and Rafael expected to be fit for Sunday's game against Liverpool, and it has become apparent to United's coaching staff that he may need strength of character, as well as ability, to continue his progress.